- 30 Nov, 2012 2 commits
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antirez authored
SDIFF used an algorithm that was O(N) where N is the total number of elements of all the sets involved in the operation. The algorithm worked like that: ALGORITHM 1: 1) For the first set, add all the members to an auxiliary set. 2) For all the other sets, remove all the members of the set from the auxiliary set. So it is an O(N) algorithm where N is the total number of elements in all the sets involved in the diff operation. Cristobal Viedma suggested to modify the algorithm to the following: ALGORITHM 2: 1) Iterate all the elements of the first set. 2) For every element, check if the element also exists in all the other remaining sets. 3) Add the element to the auxiliary set only if it does not exist in any of the other sets. The complexity of this algorithm on the worst case is O(N*M) where N is the size of the first set and M the total number of sets involved in the operation. However when there are elements in common, with this algorithm we stop the computation for a given element as long as we find a duplicated element into another set. I (antirez) added an additional step to algorithm 2 to make it faster, that is to sort the set to subtract from the biggest to the smallest, so that it is more likely to find a duplicate in a larger sets that are checked before the smaller ones. WHAT IS BETTER? None of course, for instance if the first set is much larger than the other sets the second algorithm does a lot more work compared to the first algorithm. Similarly if the first set is much smaller than the other sets, the original algorithm will less work. So this commit makes Redis able to guess the number of operations required by each algorithm, and select the best at runtime according to the input received. However, since the second algorithm has better constant times and can do less work if there are duplicated elements, an advantage is given to the second algorithm.
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antirez authored
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- 29 Nov, 2012 2 commits
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antirez authored
The idea is to be able to identify a build in a unique way, so for instance after a bug report we can recognize that the build is the one of a popular Linux distribution and perform the debugging in the same environment.
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antirez authored
1) We no longer test location by location, otherwise the CPU write cache completely makes our business useless. 2) We still need a memory test that operates in steps from the first to the last location in order to never hit the cache, but that is still able to retain the memory content. This was tested using a Linux box containing a bad memory module with a zingle bit error (always zero). So the final solution does has an error propagation step that is: 1) Invert bits at every location. 2) Swap adiacent locations. 3) Swap adiacent locations again. 4) Invert bits at every location. 5) Swap adiacent locations. 6) Swap adiacent locations again. Before and after these steps, and after step 4, a CRC64 checksum is computed. If the three CRC64 checksums don't match, a memory error was detected.
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- 28 Nov, 2012 2 commits
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charsyam authored
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Matt Arsenault authored
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- 22 Nov, 2012 5 commits
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charsyam authored
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antirez authored
EVALSHA used to crash if the SHA1 was not lowercase (Issue #783). Fixed using a case insensitive dictionary type for the sha -> script map used for replication of scripts.
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antirez authored
This fixes issue #761.
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antirez authored
After the transcation starts with a MULIT, the previous behavior was to return an error on problems such as maxmemory limit reached. But still to execute the transaction with the subset of queued commands on EXEC. While it is true that the client was able to check for errors distinguish QUEUED by an error reply, MULTI/EXEC in most client implementations uses pipelining for speed, so all the commands and EXEC are sent without caring about replies. With this change: 1) EXEC fails if at least one command was not queued because of an error. The EXECABORT error is used. 2) A generic error is always reported on EXEC. 3) The client DISCARDs the MULTI state after a failed EXEC, otherwise pipelining multiple transactions would be basically impossible: After a failed EXEC the next transaction would be simply queued as the tail of the previous transaction.
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antirez authored
We use this new bio.c feature in order to stop our I/O threads if there is a memory test to do on crash. In this case we don't want anything else than the main thread to run, otherwise the other threads may mess with the heap and the memory test will report a false positive.
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- 21 Nov, 2012 2 commits
- 19 Nov, 2012 2 commits
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antirez authored
Finally Redis is able to report the amount of memory used by copy-on-write while saving an RDB or writing an AOF file in background. Note that this information is currently only logged (at NOTICE level) and not shown in INFO because this is less trivial (but surely doable with some minor form of interprocess communication). The reason we can't capture this information on the parent before we call wait3() is that the Linux kernel will release the child memory ASAP, and only retain the minimal state for the process that is useful to report the child termination to the parent. The COW size is obtained by summing all the Private_Dirty fields found in the "smap" file inside the proc filesystem for the process. All this is Linux specific and is not available on other systems.
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antirez authored
For non Linux systmes it just returns 0. This function is useful to estimate copy-on-write because of childs saving stuff on disk.
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- 14 Nov, 2012 2 commits
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antirez authored
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antirez authored
Now that we cache connections, a retry attempt makes sure that the operation don't fail just because there is an existing connection error on the socket, like the other end closing the connection. Unfortunately this condition is not detectable using getsockopt(SO_ERROR), so the only option left is to retry. We don't retry on timeouts.
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- 12 Nov, 2012 4 commits
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antirez authored
The previous behavior was to return -1 if: 1) Existing key but without an expire set. 2) Non existing key. Now the second case is handled in a different, and TTL will return -2 if the key does not exist at all. PTTL follows the same behavior as well.
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antirez authored
When a timeout <= 0 is provided we set a default timeout of 1 second. It was set to 1 millisecond for an error resulting from a recent change.
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antirez authored
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antirez authored
While it is documented that the MIGRATE timeout is in milliseconds, it was in seconds instead. This commit fixes the problem.
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- 11 Nov, 2012 1 commit
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antirez authored
By caching TCP connections used by MIGRATE to chat with other Redis instances a 5x performance improvement was measured with redis-benchmark against small keys. This can dramatically speedup cluster resharding and other processes where an high load of MIGRATE commands are used.
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- 08 Nov, 2012 1 commit
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antirez authored
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- 07 Nov, 2012 2 commits
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antirez authored
With COPY now MIGRATE does not remove the key from the source instance. With REPLACE it uses RESTORE REPLACE on the target host so that even if the key already eixsts in the target instance it will be overwritten. The options can be used together.
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antirez authored
The REPLACE option deletes an existing key with the same name (if any) and materializes the new one. The default behavior without RESTORE is to return an error if a key already exists.
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- 06 Nov, 2012 1 commit
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antirez authored
So instead to reply with a generic error like: -ERR ... wrong kind of value ... now it replies with: -WRONGTYPE ... wrong kind of value ... This makes this particular error easy to check without resorting to (fragile) pattern matching of the error string (however the error string used to be consistent already). Client libraries should return a specific exeption type for this error. Most of the commit is about fixing unit tests.
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- 01 Nov, 2012 3 commits
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antirez authored
After the wait3() syscall we used to do something like that: if (pid == server.rdb_child_pid) { backgroundSaveDoneHandler(exitcode,bysignal); } else { .... } So the AOF rewrite was handled in the else branch without actually checking if the pid really matches. This commit makes the check explicit and logs at WARNING level if the pid returned by wait3() does not match neither the RDB or AOF rewrite child.
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Yecheng Fu authored
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antirez authored
This also fixes issue #745.
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- 31 Oct, 2012 2 commits
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Runzhen Wang authored
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antirez authored
Because of the short circuit behavior of && inverting the two sides of the if expression avoids an hash table lookup if the non-EX variant of SET is called. Thanks to Weibin Yao (@yaoweibin on github) for spotting this.
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- 30 Oct, 2012 2 commits
- 26 Oct, 2012 1 commit
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antirez authored
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- 25 Oct, 2012 2 commits
- 24 Oct, 2012 1 commit
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antirez authored
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- 22 Oct, 2012 3 commits
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antirez authored
This was an important information missing from the INFO output in the replication section. It obviously reflects if the slave is read only or not.
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Schuster authored
(Commit message from @antirez as it was missign in the original commits, also the patch was modified a bit to still work with 2.4 dumps and to avoid if expressions that are always true due to checked types range) This commit changes redis-check-dump to account for new encodings and for the new MSTIME expire format. It also refactors the test for valid type into a function. The code is still compatible with Redis 2.4 generated dumps. This fixes issue #709.
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antirez authored
In some system, notably osx, the 3.5 GB limit was too far and not able to prevent a crash for out of memory. The 3 GB limit works better and it is still a lot of memory within a 4 GB theorical limit so it's not going to bore anyone :-) This fixes issue #711
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